gistfile1.rb

  def browser_scoped_container(el='body', options={}, &block)
    namespace = 'browser_'
    html = "<!--[if lt IE 7 ]><#{el} #{tag_options(options.merge(:class => "#{namespace}ie6"))}><![endif]-->"
    html += "<!--[if IE 7 ]><#{el} #{tag_options(options.merge(:class => "#{namespace}ie7"))}><![endif]-->"
    html += "<!--[if IE 8 ]><#{el} #{tag_options(options.merge(:class => "#{namespace}ie8"))}><![endif]-->"
    html += "<!--[if (gt IE 9)|!(IE)]><!--><#{el} #{tag_options(options.merge(:class => "#{namespace}non_ie"))}><!--<![endif]-->"
    html += capture(&block)
    html += "</#{el}>"

    html
  end

see http://www.alexwelch.com/2010/09/a-different-way-of-doing-ie-specific-styles/